I would totally recommend it. I have three sewing tables and one more for a serger (which I never used ):...) and love them all. Today I emailed dreamworld company the size of the openings so they can cut inserts that are specific for my sewing machine and can't wait to order them.
One way to convince him is that your shoulders hurt now because you are sewing with a machine higher than the table and your shoulders but when you get the opening your shoulders will relax and be level (no more pain if sewing for long hours)...hey worth the shot...lol